The main structure is tested. functons like execute and write are added and tested.

other components are left

src/PostprocessData/operation/PostprocessOperation/PostprocessOperationSum.cpp

@@ -0,0 +1,71 @@
+#include "PostprocessOperationSum.hpp"
+#include "dictionary.hpp"
+#include "fieldsDataBase.hpp"
+#include "fieldFunctions.hpp"
+
+pFlow::PostprocessOperationSum::PostprocessOperationSum
+(
+    const dictionary &opDict, 
+    const regionPoints &regPoints, 
+    fieldsDataBase &fieldsDB
+)
+:
+    postprocessOperation(opDict, regPoints, fieldsDB)
+{
+    if( fieldType() == getTypeName<real>() )
+    {
+        processedRegField_ = makeUnique<processedRegFieldType>(
+            regionField(processedFieldName(), regPoints, real(0)));
+    }
+    else if( fieldType() == getTypeName<realx3>() )
+    {
+        processedRegField_ = makeUnique<processedRegFieldType>(
+            regionField(processedFieldName(), regPoints, realx3(0)));
+    }
+    else if( fieldType() == getTypeName<realx4>() )
+    {
+        processedRegField_ = makeUnique<processedRegFieldType>(
+            regionField(processedFieldName(), regPoints, realx4(0)));
+    }
+    else
+    {
+        fatalErrorInFunction<<" in dictionary "<< opDict.globalName()
+            << " field type is not supported for sum operation"
+            << " field type is "<< fieldType()
+            << endl;
+        fatalExit;
+    }
+}
+
+bool pFlow::PostprocessOperationSum::execute
+(
+    const std::vector<span<real>>& weights
+)
+{
+    auto allField = database().updateFieldAll(fieldName());
+    auto phi = database().updateFieldReal(
+        phiFieldName());
+
+    auto mask = getMask();
+    word procName = processedFieldName();
+    const auto& regP = regPoints();
+    bool dbVol = divideByVolume();
+
+    processedRegField_ = makeUnique<processedRegFieldType>
+    (   
+        std::visit([&](auto&& field)->processedRegFieldType
+            { 
+                return executeSumOperation(
+                procName,
+                field,
+                regP,
+                dbVol,
+                weights,
+                phi,
+                mask);
+            },
+            allField)
+    );
+   
+    return true;
+}